LINCOLN, Neb. 
Nebraska Lt. Gov. Rick Sheehy resigned abruptly Saturday in a scandal involving thousands of calls to four women on his state-issued cellphone, including one woman who said she had a romantic relationship with the politician.

Gov. Dave Heineman announced Sheehy's resignation in a hastily called news conference Saturday morning. Sheehy, a Republican, had been considered the front-runner in the 2014 gubernatorial race and had been endorsed by Heineman.

"As public officials, we are rightly held to a higher standard," Heineman said. "I had trusted him, and that trust was broken."

Sheehy resigned after questions were raised about the cellphone calls with four women, none of whom were his wife, who filed for divorce last year. The calls, made over the last four years, were first reported by the Omaha World-Herald, which had made a public records request for Sheehy's phone records.

Records released Saturday by the governor's office show Sheehy made thousands of late-night phone calls to the women. He spoke with some of the women numerous times a day in conversations that lasted anywhere from a few minutes to more than an hour, according to the records.

One woman he frequently called, Dr. Theresa Hatcher of Bellevue, told The Associated Press that she and Sheehy had maintained a long-term relationship after they met at a convention of emergency responders in Texas in 2008. As lieutenant governor, Sheehy leads the state's emergency management efforts, and Hatcher is an emergency room doctor.

"I thought I was the only one," she said. "Apparently, I was grossly mistaken."

Hatcher said she last talked to Sheehy about two weeks ago. She added: "Politicians can lie. Doctors don't lie."

Another woman Sheehy frequently called has had an apartment in Lincoln, the state capital. Her name appeared on a call box outside the building Saturday, but a man who answered the door said she didn't live there.

Sheehy was the mayor of Hastings before Heineman selected him as his running mate. They were elected by a record margin to their first full term in 2006 and re-elected in 2010.